For the fabrication of microelectronic devices such as light emitted diodes and flat panel displays, dry etch processing is used to selectively remove a patterned film material from the surface of a substrate. The dry etch process involves introduction of a gas into an etch chamber. The gas serving as the etch medium is excited by an applied electric field to generate a plasma. The plasma breaks down the gas into reactive species. Also, the plasma ionizes the gas, enhancing the mobility of the gas particles to transport to the substrate under the influence of the electric field. The gas ions strike the substrate surface, reacting with the specific film material to remove it from the substrate.
Please refer to FIG. 1, which is a schematic diagram of the relative position of a chamber 1 and a gauge 2 in a dry etcher. The chamber 1 is connected to the gauge 2 with a vacuum tube 3. The vacuum tube 3 is locked into the wall of the chamber 1 and is communicated with the window (not shown) of the chamber 1. Furthermore, a valve 21 is between the gauge 2 with the vacuum tube 3. When the valve 21 is opened, a sensor 22 at the front of the gauge 2 can read the pressure of the chamber 1.
As shown in FIG. 1, the plasma particles produced in the reaction in the dry etching chamber 1 directly strike against the sensor 22 whenever the valve 21 is opened and are gradually deposited on the sensor 22. After a period of time, the sensor 22 is so insensitive that the pressure of the chamber 1 cannot be accurately read and the quality of products is affected. In the current process, the sensor 22 must be frequently rectified and adjusted and even be replaced by a new one.
Therefore, the problem occurred in the gauge used to measure the pressure of the chamber of the dry etcher is desired to be solved so as to maintain the sensitivity of the gauge sensor and prolong the lifetime of the gauge.